Clutches are generally used in the prior art as a transfer mechanism of a vehicle. In U.S. Pat. No. 5,997,428, a clutch for a two-wheel vehicle and four-wheel vehicle is disclosed. A driving fork is installed between two rotary shafts for clutching the mechanism between two shafts. The prior art resolves the problem of the non-alignment as one shaft is desired to engage with another shaft. However due to the imperfect in design and space configuration, the structure is very complicated. An external space is used to install a buffer device. The structure is very complicated, the volume is great and the cost is high. Furthermore, the assembly work is tedious and time-consumed. The prior art design is uneconomic.